The patent and non-patent literature both contain disclosures of mercaptoacyl amido acid which are useful as ACE inhibitors (described above under "Related Application"). A representative disclosure is U.S. Pat. No. 4,053,651, which describes, inter alia, glycine derivatives having the formula ##STR5## wherein R.sub.d can be, inter alia, hydrogen or alkanoyl; R.sub.e can be, inter alia, alkyl of 1 to 7 carbon atoms; and R.sub.f and R.sub.g can be, inter alia, hydrogen.
U.S. Pat. No. 4,105,776 also discloses mercaptoacy amino acids. In the disclosure of how to make the compounds of that invention intermediates are disclosed having the formulas ##STR6## wherein, inter alia, R.sub.g can be hydrogen or alkanoyl; R.sub.h can be hydrogen; R.sub.i can be alkyl of 1 to 7 carbon atoms; R.sub.k can be amino; and j can be 0, 1 or 2.